JPH0756053A - Whirl stop structure for optical connector ferrule - Google Patents

Abstract

PURPOSE:To surely insert a ferrule to an optical connector housing by easily aligning respective whirl stop structures of the connector housing and the ferrule at the time of automatic assembling of an optical connector plug. CONSTITUTION:When a ferrule 1 provided with a flange 13 having a polygonal section is inserted to a housing 2, a projecting part 13a of the flange 13 comes into contact with a slope face 23 on the ferrule entrance side of a ferrule whirl stop structure 22 in the housing 2. When the ferrule 1 is inserted to the housing 2 furthermore, the slope face 23 gives a rotating force to the flange 13 of the ferrule to automatically align the whirl stop structure of the ferrule and that of the housing. Consequently, sure alignment is possible by this structure even in the case of a large positioning error in the rotating direction though it is necessary conventionally that the ferrule is inserted after accurate alignment between respective positioning structures of the ferrule and the housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical connector, and more particularly to a rotation preventing and eccentric positioning mechanism for a ferrule of the optical connector.

[0002]

2. Description of the Related Art As an example of a conventional optical connector positioning mechanism, JP-A-57-74714 and JP-A-59-1 are used.
25706, JP 62-0709 A, JP 62-138805 A, JP 62-20530 A.
No. 3, Japanese Utility Model Laid-Open No. 63-78906, Japanese Unexamined Patent Publication No.
There is, for example, Japanese Patent No. 25405.

FIG. 7 shows a vertical cross section of a main example of a conventional ferrule positioning structure for an optical connector plug. In FIG. 7, a cross section AA is a partial cross sectional view of the flange portion of the housing 82 and the ferrule 81. The ferrule positioning structure in the conventional optical connector plug has a block-shaped convex portion 87 provided in the housing 82 and a slit-shaped concave groove 8 provided in the flange of the ferrule 81 as shown in this figure.
5, or a combination of a block-shaped convex portion provided on the flange of the ferrule 81 and a slit-shaped concave groove provided on the housing 82 (not shown) in the opposite configuration. Was there.

Further, as another example of the prior art, Japanese Patent Laid-Open Publication No.
There is an example described in JP-A-7-74714. FIG. 8 is a sectional view showing the structure of Japanese Patent Laid-Open No. 57-74714. In FIG. 8 (a), reference numeral 116 is a ferrule in which a fiber is mounted in a metal sleeve, and reference numeral 125.
Is a detent having a plurality of wedge-shaped protrusions formed on its one end face in the radial direction on the one side, and this detent is provided with a protrusion 125a for preventing the ferrule 116 from rotating. An adapter and a receptacle (FIGS. (B) and (c)) that mate with an optical connector plug having a ferrule to which the detent 125 is attached are provided with a detent receiver 131 having the same wedge shape as the detent 125. Has been. Due to such a structure, there is a feature that these plugs can be smoothly engaged with each other by simply inserting the plug into the receptacle without performing alignment.

[0005]

In assembling the above-described conventional optical connector plug, it is necessary to manually fit the housing positioning structure (convex portion) and the ferrule positioning structure (concave groove). It was Generally, in order to reduce the loss, the optical connector is assembled with the eccentric direction of the core of the optical fiber and the direction of the eccentric alignment key of the housing being the same. However, since the fitting portion is a place such as the back of the housing that is difficult to see with the naked eye, it is easy to cause a fitting failure such as assembling with these key directions wrong. Further, it is difficult to accurately fix the housing and the ferrule with the positioning keys by using the automatic assembling apparatus.

That is, in the example of the conventional optical connector plug shown in FIG. 7, the rotation stopping structure is constituted by the combination of the concave groove 85 provided on the flange of the ferrule 81 and the convex portion 87 provided inside the housing 82. Was. With such a rotation stop structure, it is necessary to visually check the engagement of the concave groove and the convex portion, which is necessary when assembling the connector, and it is difficult to reliably insert the ferrule into the housing using the automatic assembly device. There was a drawback that

Further, Japanese Patent Laid-Open No. 57-7471 shown in FIG.
The example of the four publications has a feature that the plug and the adapter can be engaged smoothly even if they are joined without visually confirming the position of the detent, but they also have the following drawbacks. A so-called butt joint type optical connector in which optical fibers are butted against each other to connect optical paths has a structure in which a coil spring or the like is used to press the ferrule and a pressing force is always applied to the tip of the ferrule. In order to ensure a stable connection, it is important to set the rotational position of the ferrule with high accuracy and the axial position accuracy. In the example of Japanese Patent Laid-Open No. 57-74714, since the engagement is performed by wedge-shaped engagement, when the optical connector plug and the receptacle are engaged with each other, if a twisting force is applied to the optical fiber cable, the ferrule will be Rotate a lot,
The ferrule end surface and the mechanical reference surface inside the receptacle were sometimes separated greatly. Also, when connecting the adapter, the spring inside the optical connector plug is connected in a slightly bent state, so a wedge-shaped rotation stopper on the plug side,
There was a gap between the wedge-shaped rotation stopper on the adapter side, the degree of freedom in the rotation direction of the ferrule increased, the positioning could not be uniquely determined, and the loss variation when attaching and detaching the connector plug increased. . In particular, the single mode optical fiber that requires highly accurate positioning in the rotation direction of the ferrule as today, and the end face of the ferrule is processed into a convex spherical surface to directly contact the optical fibers,
PC (physica) that suppresses the generation of reflected light at the connection part
However, it has been a fatal drawback when applied to an (l contact) type optical connector.

[0008]

A rotation preventing structure for an optical connector ferrule according to the present invention comprises a cylindrical capillary for inserting and holding and fixing an optical fiber on a central axis, and a capillary located at a substantially central portion of the capillary. A ferrule formed of a tubular member provided with a rotation preventing and positioning flange having a regular polygonal cross-section on the side opposite to the insertion side of the optical fiber; the ferrule having one side opening A housing that is included from the end to form the body of the optical connector plug; a spring that biases the ferrule toward the tip of the optical connector plug; and a ring component that encloses and holds the ferrule and the spring in the housing. And an abutting surface that abuts against one end surface of the positioning flange of the ferrule inside the housing. The ferrule detent step has a cross-sectional shape similar to the cross-sectional shape of the rotation preventing and positioning flange of the ferrule from the abutting surface toward the opening end side of the housing and has a slightly large cross-sectional area. A portion is formed, and a slope surface is provided from the ferrule detent step to the opening end side of the housing, and the slope surface extends from the center of the flat portion of the ferrule detent step to the housing. It is divided into two surfaces with the ridge extending to the opening end side as the apex,
Further, it is composed of an inclined portion in which the inclination of the ridgeline gradually increases toward the opening end side of the housing.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. The type of the optical connector quoted in this embodiment is an F04 type single-core optical fiber connector established in Japanese Industrial Standard JIS C5973, and the fastening method is push-on fastening with a slide lock structure, and the optical coupling method is Butt joint method, mechanical connection method is plug-
The adapter-plug method and the optical fiber alignment method have an outer diameter of 2.
It has a feature of a 5 mm ferrule structure.

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention, FIG. 2 is a perspective view partially showing a state in which a ferrule is being inserted into a housing, and FIG. 3 is each part of this embodiment. FIG.

The ferrule 1 has a capillary 11 provided with fine holes for holding the optical fiber 3 on the central axis with high precision, and a capillary 13 provided with a convex portion 13a on a flange 13 for preventing the capillary 11 from rotating. Holding member 12
It consists of and. An optical fiber 3 is held and fixed on the center axis of the ferrule 1, and in the present embodiment, the flange 13 including the convex portion 13a has a regular tetragonal cross section. The housing 2 is a housing component of the optical connector plug of the present embodiment, and is made of synthetic resin that is easily moldable. Therefore, even if the external and internal parts have complicated shapes, mass production can be easily performed by the injection molding method. A fastening protrusion 24 for mechanically fastening the optical adapter is provided on the outside of the housing 2, and is provided on an elastic locking piece inside the optical adapter when fastening the optical connector plug and the optical adapter. The structure is such that it is engaged with the engaged claw (not shown). Further, the housing 2 has a rectangular outer cross-sectional shape and does not easily rotate after being fastened to an optical adapter having a similar rectangular opening. A chamfer is formed on one side of the outside of the housing 2 to engage with a positioning projection of the opening of the optical adapter, and to restrict the position of the optical connector plug in the rotation direction to one direction when the optical adapter and the optical connector plug are engaged. 26 is formed (see FIG. 3). An abutment surface 21 is formed inside the housing 2 to abut against one end surface of the flange 13 of the ferrule 1 and prevent the ferrule 1 from protruding toward the tip side (rightward in FIG. 1). From this butting surface 21 to the housing 2
A ferrule detent step 22 having a cross-sectional shape similar to the cross-sectional shape of the flange 13 of the ferrule 1 and a slightly larger cross-sectional area is formed toward the rear part (the insertion direction of the optical fiber 3, leftward in FIG. 1). There is. A slope surface 23 is provided from the ferrule detent step 22 toward the rear of the housing 2. The slope surface 23 has a ridge line 23a extending from the central portion of the flat surface portion 22a of the ferrule rotation stopping step portion 22 to the rear portion of the housing 2 as an apex.
It is composed of an inclined portion 23b which is divided into surfaces and in which the inclination of the ridge line 23a gradually increases toward the rear portion of the housing 2. Near the rear opening of the housing 2, there is formed a ring stop projection 25 that engages with a locking projection 52 of the ring component 5 described later and fixes the ring component 5.

The spring 4 is set so that one end thereof abuts on the flange 13 of the capillary holding member 12, and the other end abuts on a protrusion 51 provided on the inner surface of a cylindrical ring component 5 described later. ing. Since this spring 4 is in a compressed state after the optical connector is assembled,
The ferrule 1 is always biased toward the tip side of the optical connector plug. The ring component 5 has a cylindrical portion 51 having an inner diameter slightly smaller than the maximum outer diameter of the flange 13 of the ferrule 1 on the tip side, and a step portion 52 for receiving one end surface of the spring 4 therein.
Is a cylindrical part that engages with the ring stopper protrusion 25 of the housing 2 and has a locking collar 53 formed on the outer periphery for coupling and fixing with the housing 2.

Next, a procedure for assembling the optical connector plug having the structure of this embodiment using the automatic assembling apparatus will be described.

The step of assembling the optical connector plug includes the step 1 of aligning the eccentric direction of the optical fiber core of the ferrule 1 with the positioning structure of the housing 2.
Step 2 of inserting the ferrule 1 into the housing 2, step 3 of inserting the spring 4 into the housing 2, and insertion of the ring component 5 into the housing 2 and the ferrule 1 and the spring 4
And 4 are fixed in the housing 2.

The measurement system of step 1 for determining the direction of eccentricity of the optical fiber core will be described with reference to FIG. Light is incident on the optical fiber 3 from a light source 60 installed at the end of the optical fiber 3 where the optical connector plug is installed. Next, the end face of the ferrule 1 is observed by the camera 61, and the pattern of the light emitted from the core portion of the optical fiber 3 is processed by the image processing device 62. The eccentric direction 65 of the fiber core is obtained. The direction perpendicular to the plane portion of the flange 13 which is the closest to the obtained eccentric direction 65 is defined as the eccentricity deemed direction 66 of the optical fiber core.

In step 2, the ferrule 1 is inserted from the rear opening of the housing 2 while aligning the flat surface of the flange in the eccentricity direction 66 of the optical fiber core with the chamfer 26 which is a guide for positioning the housing 2 in the eccentric direction. At this time, even if the respective positions in the rotation direction are slightly deviated from each other, the protrusion 13a of the flange 13 of the ferrule 1 is not
The ferrule 1 rotates in contact with the internal slope surface 23 so that the outer shape of the flange 13 and the cross-sectional shape of the ferrule rotation stopping step portion 22 of the housing 2 match. If you continue inserting ferrule 1 here, slope surface 2
3 and the flat surface portion 22a are continuously formed, the flange 13 of the ferrule 1 smoothly fits into the ferrule rotation stopping step portion 22 of the housing 2 without being caught in the middle. Finally, the step of inserting the ferrule 1 into the housing 2 is completed at the position where the end surface of the flange 13 abuts against the ferrule abutting surface 21 of the housing 2. Since the slope surface 23 automatically guides the mating portion of the housing 2 while rotating the ferrule 1, the positioning accuracy between the flange 13 of the ferrule 1 and the chamfer 26 of the housing 2 is higher than that of the conventional optical connector plug. Is ± 5
While it is necessary to have an accuracy of less than or equal to a degree, it is possible to surely engage with each other even at about ± 35 degrees.

Next, the spring 4 is attached to the flange 13 of the ferrule 1.
When the ring component 5 is inserted into the housing 2 after being inserted until it abuts on the end face of the, the step portion 52 for receiving the spring 4 inside the ring component 5 first abuts on the spring 4. Subsequently, when the ring component 5 is continuously inserted, the spring 4 is compressed, and then the locking collar 53 formed on the outer peripheral portion of the ring component 5 engages with the ring stopper projection 25 inside the housing 2 to cause the ring component 5 to move. The conclusion is complete. When the fastening of the ring component 5 is completed, the ferrule 1 is always urged by the spring 4 toward the tip side (the insertion direction of the optical fiber 3), and when the optical connector is connected, stable connection is secured. Further, since the inner diameter of the cylindrical portion 51 at the tip of the ring component 5 is set smaller than the maximum outer diameter of the flange 13 including the protrusion 13a of the ferrule 1, a large pressing force is applied to the tip of the ferrule 1. In this case, since the flange 13 of the ferrule 1 first hits the tip of the ring component 5 and the back amount of the ferrule 1 is mechanically restricted, the protrusion 13a for preventing rotation of the flange 13 of the ferrule 1 is fixed to the ferrule of the housing 2. It does not come off from the rotation stop 22. Therefore, there is no problem that the rotation stopping structure of the housing 2 and the ferrule 1 is disengaged, the eccentric direction of the optical fiber core is deviated, and the optical characteristics are not stable when the optical connector plug is attached and detached.

In this embodiment, the protrusion 13 for stopping rotation is provided.
Although the case where the cross-sectional shape of the flange 13 including a is a regular tetragon is illustrated, the same effect can be expected when a polygon such as a regular hexagon is used as shown in FIG. 6C.

Further, the flange 1 of the ferrule 1 is shown in FIG.
A second embodiment is shown in which the housing insertion side end of the convex portion 13a of No. 3 and the ferrule introduction portion of the slope surface 23 of the housing 2 are chamfered 14 and 27 respectively. First
In the embodiment, when inserting the ferrule 1 into the housing 2, when the housing insertion side end of the convex portion 13a of the flange 13 of the ferrule 1 and the ferrule introducing portion of the slope surface 23 of the housing 2 interfere with each other, The ferrule 1 may be difficult to insert into the housing 2 or may be improperly inserted. However, as in the second embodiment, proper chamfering of the interference portion ensures smooth insertion. As a result, the ferrule can be surely inserted. In this case, by using synthetic resin as the material of the capillary holding member 12 of the ferrule 1, mass production by the injection molding method is possible even if the capillary holding member 12 has a complicated shape, and the cost can be reduced.

[0020]

In the conventional optical connector plug, when the housing positioning structure (for example, projection) and the ferrule positioning structure (for example, groove) are inserted in the same rotational direction, the housing projection and ferrule are inserted. The parts other than the positioning structure, such as the flange surface, may interfere with each other and may not be inserted properly. Also in the optical connector plug according to the first embodiment of the present invention, when the convex portion 13a of the ferrule 1 and the protruding portion of the slope surface 23 of the housing 2 into the housing interfere with each other, the insertion failure may occur. is there. When the ferrule 1 is inserted into the housing 2 in a random rotational direction, the probability that the flange surface or the positioning protrusion interferes with the internal structure of the housing and makes insertion impossible is due to the internal structure of the housing. It can be expressed by the following formula: angle range × number of times that normal mating can be performed during one rotation of the ferrule / 360 degrees. FIG. 6A is a sectional view showing a mating state of a conventional optical connector plug positioning structure, and FIG. 6B shows a mating state of the optical connector plug positioning structure of the first embodiment of the present invention. FIG. 6C is a sectional view showing a mating state when the flange 13 of the ferrule 1 and the ferrule rotation stopping step portion 22 of the housing 2 have a hexagonal sectional shape. The dimensions of the gap between the housing 2 and the ferrule 1 were all set to 0.2 mm for the study. In FIG. 6, the angular range of interference with the structure inside the housing is about 170 degrees in the case of FIG. 6A, about 20 degrees in the case of FIG. 6B, and about 11.5 in the case of FIG. 6C. The insertion failure rate is 170 × 2 ÷ 360 = 0.9, respectively.
4, 20 × 4 ÷ 360 = 0.22, 11.5 × 6 ÷ 36
0 = 0.19, which is 4 to 5 times easier to insert in both cases of FIGS. 6B and 6C than the conventional optical connector plug positioning structure of FIG. 6A. Was confirmed. Further, as shown in FIG. 5, the chamfering 14 and the chamfer 27 are performed on the housing insertion side end of the convex portion 13a of the flange 13 of the ferrule 1 and the ferrule introduction portion of the slope surface 23 of the housing 2, respectively, so that the insertion failure occurs It becomes possible to make the rate almost 0 (%).

As described above, the optical connector plug according to the present invention has an effect that the ferrule can be easily inserted into the housing even if the position of the ferrule in the rotating direction is not accurately set. After being completed as, as in the conventional optical connector, the eccentric direction of the optical fiber core and the positioning accuracy at the time of attaching and detaching the optical connector plug can be maintained with extremely high accuracy. It becomes possible to secure high optical performance.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of an optical connector plug of the present invention.

FIG. 2 is a perspective view partially showing a state in which the ferrule is being inserted into the housing in the present embodiment.

FIG. 3 shows an assembled state of the present embodiment, (a) is a longitudinal sectional view, (b) is a front view, and (c) and (d) are respectively BB line and A- line in FIG. It is sectional drawing in the A line.

FIG. 4 is a block diagram showing a general measuring method of an eccentric direction of an optical fiber core.

FIG. 5 is an exploded perspective view showing a second embodiment of the optical connector plug of the present invention.

6A and 6B are sectional views showing a cross-sectional shape of a rotation stopper structure, FIG. 6A is a conventional example, FIG. 6B is a present example, and FIG. 6C is another example.

FIG. 7 shows an example of a conventional optical connector plug, (a)
Is a vertical sectional view, (b) is a front view, and (c) is A in FIG.
It is a sectional view taken along the line A.

FIG. 8 shows a conventional optical connector plug having a rotation stopping structure with a wedge-shaped cross section, (a) is a cross sectional view, (b) is a cross sectional view of an adapter, and (c) is a view showing a shape of an engaging portion. is there.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ferrule 11 Capillary 12 Capillary holding member 13 Flange 13a Convex part 14 Chamfer 2 Housing 21 Ferrule abutting surface 22 Ferrule anti-rotation step part 22a Flat part 23 Slope surface 23a Ridge line 23b Inclined part 24 Fastening protrusion 25 Ring stop protrusion 26, 27 Chamfer 3 Optical fiber 4 Spring 5 Ring part 51 Cylindrical part 52 Step part 53 Locking collar 60 Light source 61 Camera 62 Image processing device 63 Monitor 64 Eccentricity of optical fiber core center with respect to ferrule outer diameter 65 Optical fiber core eccentric direction 66 Optical fiber Eccentricity of core

Claims (3)

[Claims] 1. A cylindrical capillary for inserting and holding and fixing an optical fiber on a central axis, and a regular polygonal shape on the side opposite to the insertion side of the optical fiber, which is located at substantially the center of the capillary. A ferrule constituted by a tubular member provided with a rotation preventing and positioning flange having a cross section; and a housing which forms the main body of an optical connector plug by including the ferrule from an opening end on one side; An optical connector plug comprising a spring for urging the ferrule in the direction of the tip of the optical connector plug, and a ring component for holding and fixing the ferrule and the spring in the housing, the optical connector plug being provided inside the housing. Has an abutting surface that abuts against one end surface of the positioning flange of the ferrule, and from the abutting surface to the opening end side of the housing. A ferrule detent step having a cross-sectional shape similar to that of the flange for preventing rotation and positioning of the ferrule and having a slightly large cross-sectional area is formed, and the ferrule detent step further forms the opening of the housing from the ferrule detent step. A slope surface is provided toward the end side, and the slope surface is divided into two surfaces with a ridge line extending from the central portion of the flat surface portion of the ferrule rotation stopping step portion to the opening end side of the housing as an apex, and An anti-rotation structure for an optical connector ferrule, comprising an inclined portion in which the inclination of the ridge gradually increases toward the opening end side of the housing. 2. The optical connector ferrule according to claim 1, wherein the ferrule insertion side end of the slope surface and the housing introduction side end of the flange of the ferrule are chamfered respectively. Anti-rotation structure. 3. The capillaries and the housing are made of synthetic resin.
Alternatively, the optical connector ferrule rotation stopping structure described in 2.